The British Association of Social Workers (BASW) has said that it was "surprised" and "disappointed" to find that the College of Social Work has decided to go ahead with developing a college which "excludes BASW".

In an open letter to the college Fran Fuller, chair of BASW, says that the plans were a surprise, as the organisations have a memorandum of understanding in place and have spent "many weeks" positively discussing the college's development.

"Of course the creation of a joint college is a complex process but the development of a transition board and the imminent prospect of us taking proposals to our members for their approval on 1 November is clear evidence that we were working together coherently within your acknowledged timescale," says Fuller.

"While you have been unable to provide us with full information about your proposed relationship with Unison we have been clear that what we have learnt so far has caused us no difficulty and we were looking forward to getting around the table with all concerned in the expectation that we could make an agreement."

Fuller goes on to say that in order to delay its final recommendations as long as possible, BASW will hold an extra council meeting on 31 October to provide it with a five week period in which to negotiate and agree on the union issue. This will also give the association time to provide its members with the information which will "hopefully enable them to vote for the creation of a college which will serve their profession well".

In a statement on its website, the college said that in spite of negotiations to merge with BASW, it had proved impossible to reach agreement with the association within the necessary timescales, so it had decided to continue without BASW. However, the college added that it was prepared to continue discussions with the association once it is established and operational. This sentiment was echoed in Fuller's letter, which says "no one wants a divided profession", adding that BASW will work to create a joint and united college despite the latest disagreement.

The creation of the college was recommended by the government's social work taskforce in January 2010.